(ABC News) - Lacking a "statutory rape" option for his relationship status on Facebook, a 27-year-old Pennsylvania man declared he was engaged to a 14-year-old girl, tipping off cops who arrested the man for an unlawful relationship with a girl half his age.
Robert Nickson Jr. told cops in Delaware County, Penn. that he met the girl in late July through a mutual friend. Over the course of one month, Nickson bought the girl, unidentified in court documents because of her age, an engagement ring and they each announced they were "in love" and "engaged" on Facebook.
According to police, Nickson knew the girl was underage and their relationship was unlawful, but took her home to the house he shared with his father to have sex with her at least four times.
"[The girl] stated that her [sic] and Nickson have had various conversations about how it was against the law, but 'didn't think they would get caught,'" reads the police report.
A Delaware County Criminal Investigation Division's special task force, nicknamed Operation Triad, which investigates child pornography and predators, was tipped off by the county's child welfare agency after Nickson posted photos of himself and the girl online.
The Facebook profiles of both Nickson and the girl include pictures of them together. Nickson's profile has since been taken down.
Prosecutors say they found further proof that Nickson knew the girl's age and that his actions were illegal by viewing text messages he sent her.
"I wish I had my own place and you lived with me that I would get to see you everyday no matter what time I get done and no one would know where it is," Nickson texted the girl.
Later, once he knew law enforcement was investigating him, he wrote: "we just have to lay low."
Nickson was arraigned on Sept. 9, 2010. He is charged with four counts of statutory sexual assault, aggravated assault and corruption of a minor.
Man Declares Himself 'Engaged' to 14-Year-Old on Facebook
In Pennsylvania, felony sexual assault is defined as sex with someone under 16, when the person is four or more years older.
Nickson, who is in county jail awaiting a hearing, has yet to enter a plea or hire a lawyer. His bail was set at $100,000.
Calls to his father's home were not answered.
For more stories from ABC News, click here to go to ABCNews.com